—Have you been to the United States?
—Yes, only once. I there only for seven days.
A. stayed
B. had stayed
C. have stayed
D. was staying
网友回答
(答案→)A. stayed
B. had stayed
C. have stayed
D. was staying
解析：考查动词的时态。据句子 Have you been to the United States? Yes, only once.我去过美国，但已经回来，所以I there only for seven days是过去的事，所以应用一般过去时态。选A。